Remove transposed Jacobian fields from mjData

No longer computed unconditionally, only ad-hoc where required.

PiperOrigin-RevId: 797753297
Change-Id: I2030fc342c98ff33575b0526dd72e2110c4fcb74

src/engine/engine_core_constraint.c

@@ -386,10 +386,10 @@ void mj_mulJacTVec(const mjModel* m, const mjData* d, mjtNum* res, const mjtNum*
   }
 
   // sparse Jacobian
-  if (mj_isSparse(m))
-    mju_mulMatVecSparse(res, d->efc_JT, vec, m->nv,
-                        d->efc_JT_rownnz, d->efc_JT_rowadr,
-                        d->efc_JT_colind, d->efc_JT_rowsuper);
+  if (mj_isSparse(m)) {
+    mju_mulMatTVecSparse(res, d->efc_J, vec, d->nefc, m->nv,
+                        d->efc_J_rownnz, d->efc_J_rowadr, d->efc_J_colind);
+  }
 
   // dense Jacobian
   else {
@@ -1996,12 +1996,6 @@ void mj_makeConstraint(const mjModel* m, mjData* d) {
 
   // transpose sparse Jacobian, make row supernodes
   if (mj_isSparse(m)) {
-    // transpose
-    mju_transposeSparse(d->efc_JT, d->efc_J, d->nefc, m->nv,
-                        d->efc_JT_rownnz, d->efc_JT_rowadr, d->efc_JT_colind, d->efc_JT_rowsuper,
-                        d->efc_J_rownnz, d->efc_J_rowadr, d->efc_J_colind);
-
-
 #ifdef mjUSEAVX
     // compute supernodes of J; used by mju_mulMatVecSparse_avx
     mju_superSparse(d->nefc, d->efc_J_rowsuper,

src/engine/engine_island.c

@@ -597,20 +597,6 @@ void mj_island(const mjModel* m, mjData* d) {
       mju_superSparse(d->island_nefc[island], d->iefc_J_rowsuper + adr,
                       d->iefc_J_rownnz + adr, d->iefc_J_rowadr + adr, d->iefc_J_colind);
     }
-
-    // block-diagonalize Jacobian-transpose
-    mju_blockDiagSparse(d->iefc_JT, d->iefc_JT_rownnz, d->iefc_JT_rowadr, d->iefc_JT_colind,
-                        d->efc_JT, d->efc_JT_rownnz, d->efc_JT_rowadr, d->efc_JT_colind,
-                        nidof, nisland,
-                        d->map_idof2dof, d->map_efc2iefc,
-                        d->island_idofadr, d->island_iefcadr, NULL, NULL);
-
-    // recompute rowsuper per island
-    for (int island=0; island < nisland; island++) {
-      int adr = d->island_idofadr[island];
-      mju_superSparse(d->island_nv[island], d->iefc_JT_rowsuper + adr,
-                      d->iefc_JT_rownnz + adr, d->iefc_JT_rowadr + adr, d->iefc_JT_colind);
-    }
   }
 
   // copy position-dependent efc vectors required by solver

src/engine/engine_print.c

@@ -1236,8 +1236,6 @@ void mj_printFormattedData(const mjModel* m, const mjData* d, const char* filena
     printArrayInt("EFC_J_ROWADR", d->nefc, 1, d->efc_J_rowadr, fp);
     printSparse("EFC_J", d->efc_J, d->nefc, d->efc_J_rownnz,
                 d->efc_J_rowadr, d->efc_J_colind, fp, float_format);
-    mj_printSparsity("JT: constraint Jacobian transposed", m->nv, d->nefc, d->efc_JT_rowadr, NULL,
-                     d->efc_JT_rownnz, d->efc_JT_rowsuper, d->efc_JT_colind, fp);
     if (mj_isDual(m)) {
       printArrayInt("EFC_AR_ROWNNZ", d->nefc, 1, d->efc_AR_rownnz, fp);
       printArrayInt("EFC_AR_ROWADR", d->nefc, 1, d->efc_AR_rowadr, fp);